Spatial power-combining devices, such as a Qorvo® Spatium® spatial power-combining device, are used for broadband radio frequency power amplification in commercial and defense communications, radar, electronic warfare, satellite, and various other communication systems. Spatial power-combining techniques are implemented by combining broadband signals from a number of amplifiers to provide output powers with high efficiencies and operating frequencies. One example of a spatial power-combining device utilizes a plurality of solid-state amplifier assemblies that form a coaxial waveguide to amplify an electromagnetic signal. Each amplifier assembly may include an input antenna structure, an amplifier, and an output antenna structure. When the amplifier assemblies are combined to form the coaxial waveguide, the input antenna structures may form an input antipodal antenna array, and the output antenna structures may form an output antipodal antenna array.
In operation, an electromagnetic signal is passed through an input port to an input coaxial waveguide section of the spatial power-combining device. The input coaxial waveguide section distributes the electromagnetic signal to be split across the input antipodal antenna array. The amplifiers receive the split signals and in turn transmit amplified split signals across the output antipodal antenna array. The output antipodal antenna array and an output coaxial waveguide section combine the amplified split signals to form an amplified electromagnetic signal that is passed to an output port of the spatial power-combining device.
The performance of spatial power-combining devices depends on a number of parameters, including the size and spacing of amplifier assemblies relative to each other. In particular, the size and spacing of amplifier assemblies in a coaxial arrangement about a center axis is relatively important for a given operating frequency range and bandwidth of the spatial power-combining device. If the spacing between the amplifier assemblies it too great, the device does not function; if the spacing between the amplifier assemblies is too close, there may be interference. Additionally, phase variation between amplifiers of different amplifier assemblies for a given operating frequency range may contribute to degradation of power-combining efficiency.